Question

In a model of a ship, the mast is 9 cm high, while the mast of the actual ship is 12 m high. If the length of the ship is 28 m, how long is the model ship?

Answer 1

Let the length of model ship be x.
$\begin{array}{ccc}Lengthofactualship\left(inm\right)& 12& 28\\ Lengthofmodelship\left(incm\right)& 9& x\end{array}$

Here length of mast and actual length of ship are in direct proportion.

$\therefore \frac{12}{9}=\frac{28}{x}\Rightarrow x\times 12=28\times 9\Rightarrow x=\frac{28\times 9}{12}=21cm$
Hence, the length of the model ship is 21 cm.